Yes, have the vet do geriatric blood work, but you may be seeing the first signs of canine dementia. A change in food wouldn’t hurt, not necessarily senior food, a lot of them are rubbish and marketing and totally ignore what a senior dog’s actuall needs are. Seniors often digest proteins less efficiently and can need up to 50% more high quality protein. One way to meet this need is to start topping his food with canned food or protein rich fresh food toppers like eggs, sardines, kefir, lean meat table scraps, etc. If you have been feeding once a day, you might want to go back to feeding twice a day, so he doesn’t have an empty belly.
If he is starting to get dementia, the first thing to go is inhibition, so they start doing thing that they formerly wouldn’t do because they knew you didn’t like it. Which can mean that they also revert to puppy chewing on inappropriate things, so watch for that sort of behavior and if you start seeing him reverting, he may need to be crated while you are gone, to keep him safe.
